SEROTONIN SYNDROME

A, B, C i.e. Tremors, Agitation, Cardiovascular collapse

Ans. is ‘a’ i.e., Chlorpromazine

Serotonin syndrome

o Serotonin syndrome refers to a dangerous and potentially fatal syndrome caused by excess synaptic serotonin levels due to use of serotonin potentiating drugs.

o This condition is associated confusion, altered conciousness, hyperthermia, tremors, myoclonus, rigidity and hyperreflexia.

o Drugs causing serotonin syndrome are :‑

1.     Inhibiting 5-HT metabolism :- MAO inhibitors (e.g. tranylcypromine, phenelzine, meclobemide, selegilline)

2.     Inhibit serotonin reuptake SSRls, TCAs, amphetamine, cocaine, pethidine (mepridine), Pentazocin, MDMA, tramadol, Nefazodone, dextromethrophon.

3.     Increase 5-HT release :- Amphetamine, cocaine, fenfluramine, MDMA, sibutramine.

4.     Serotonin Agonists Buspirone, lithium, LSD, Ergots (Dihydroergotamine), triptans (Sumitriptan), Piperazine.

5.     Other :- ECT, trazodone / Nafazodone, Carbamezapine.

Ans. is ‘c’ i.e., Dantrone is the drug of choice

• Serotonin syndrome closely resembles neuroleptic malignant syndrome. However, in contrast to neuroleptic malig­nant syndrome it is not an idiosyncratic drug reaction and is generally dose related.
• Serotonin syndrome is due to acute overstimulation of 5-HT₂A receptors caused by serotonergic drugs like SSRI (Drugs causing serotonin syndrome have been explained)

Treatment of Serotonin Syndrome

o Treatment of patients with serotonin syndrome begins with supportive care and decreasing muscle rigidity.

o Because muscle rigidity is thought to be partly responsible for hyperthermia and death, external cooling in conjunc‑

tion with aggressive use of benzodiazepines should limit complication and mortality. In severe cases, neuromuscular

Mocker should be considered to achieve rapid muscle relaxation.

• Use of Cyproheptadine in patients with mild/moderate serotonin syndrome has shown effective serotonin blockage and control of symptoms.
• Other drugs that are antedotally reported to be successful for the treatement of symptoms of serotonin syndrome include methysergide, chlorpromazine, atypical antipsychotics and propranolol.
• In most patients, the serotonin syndrome resolves within 24 hours after the offending drug is removed.

o Aggressive cooling and sedation with a benzodiazepine remain the basis of therapy.

Ans. D: Sumatriptan action is agonistically 5-HT 113/1D receptor mediated

Cisapride and renzapride are selective 5-HT4 agonists.

• Ondansetron is a selective 5-HT3 antagonist which inhibits vomiting by blocking these receptors in brainstem as well as in gut wall.
• Cyproheptadine is 5-HT2A antagonist and has additional H1 antihistaminic, anticholinergic and sedative properties.
• Sumatriptan and other triptan are selective 5-HT 113/1D agonists, constricts cerebral blood vessels and has emerged as the most effective treatment of acute migraine attacks.

Ans. is ‘a’ i.e., D2

Cyproheptadine

• It primarily blocks 5HT2A receptors and has additional HI antihistaminic, anticholinergic and sedative properties.
• It is used in allergies and as an antipruritic agent.
• It increases appetite and has been used in children and poor eaters to promote weight gain.
• It is used in controlling intestinal manifestations of carcinoid and post gastrectomy dumping syndrome as well as in antagonizing priapism/ or orgasmic delay caused by fluoxetine and trazodone.